Expansion Joints for iron and steel industry has a large amount of dust and soot emissions and its properties are diverse. The dust collectors used for dust and dust treatment include wet dust collectors, electrostatic precipitators and bag filter.

Because of the low dust removal efficiency, the wet dust collector has a large amount of water and generates secondary water pollution, and has basically been eliminated. The electrostatic precipitator has high efficiency, can reach 99.0%, temperature resistance is up to 350°C, resistance is small, about 200 Pa～300 Pa, and the processing air volume is large, reaching 106m3/h or more. It was used in steel industry, but due to its application ratio Resistance range 104 ~ 1010Ω.cm, due to changes in the physical and chemical properties of dust, and can not adapt to changes in process conditions and load. In the iron and steel industry, there are a large variety of dust and soot, with a large specific resistance change. Many specific resistances are beyond their applicable range, and some process conditions change greatly. As a result, their dust removal efficiency is unstable, often falling below 90%, resulting in frequent emission concentrations. Fluctuations, it is difficult to maintain the emission concentration of <100 mg/Nm3 for a long period of time under different working conditions. Therefore, it is rarely used so far.